George a



(No Model.)

G. A. FITCH.

SPEAKING TELEPHONE.

Patented 1300.26, 1882.

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mania WITNBSSES ma M INVENTOR u!! ATTORNEYS.

IINTTED STATES PATENT artica.

' GEORGE A. FITCH, OF OAKLAND, NEV YORK.

SPEAKING-TELEPHONE'.

SPECIFICATION forming part of Letterslatent No. 269,657, dated December26, 1882,

Application tiled March 4, 1882. (No model.)

To ali whom it muy concern:

Be it known that I, GEORGE A. FrroH, of Oakland, in the county ofLivingston and State of New York, have invented anew and uset'ulimprovement iu Speaking-Telephones, ot'v adj listing-spring to preventit from respon ding to induced or minor currents. When an electriccurrent is passed through the rotating rollers and the strip thefriction between the said parts will be increased or diminished inproportion to the varyingintensity of the current, and a correspondingvibration of the diaphragm will be produced.

In the accompanying drawings, Figure lis a vertical section ot' aninstrument embodying my invention. Fig. 2 is a horizontal section ot'the same. Fig. 3 is an edge view of the rollers and armature, the latterbeing in section. Fig. 4 is a vertical section ot' an instrument,

showing the rollers arranged in the reverse or der ot' that shown inFig. l; and Fig. 5 shows a modified form of roller and strip.

`In loud-speaking telephones it has been attempted heretot'ore toconnect a receiving-diaphragm with a transmitting` apparatus by means ofa strip ot' metal which is connected to the diaphragm and arranged undera given pressure between two chemically-prepared rotating rollers,whereby when a current v'is passed through 'the rollers and the stripthe passage of the current shall act as a lubricantl between the stripand rollers and cause the pressure on the strip tobe released atintervals, thus causing the variations ofthe current to be recorded invibrations ofthe diaphragm. In my invention, on the contrary, I dispensewith the chemical element ot' the apparatus and employ a roller which isadapted to be rotated by hand-gear, clock-work, or by electromagnetism,and a pressure roller whichis placed in connection with anelectro-magnet by means of' an adjustable armature in such manner thatthe latter roller shall be made t0 bear with a variable pressure on asuitable strip connected to the4 diaphragm.

The arrangement ofthcse. parts will be clearly understood by referenceto the drawings, in which A represents the mouth-piece,13 the diaphragm,and O a box in which are supported hy the frame vD the magnets E E, therevolving armature F, and the rotating roller G,the

said magnets and armature constituting the` electro-motor. A secondroller, II, is adapted to rotate on a spindle attached to the armatureI, while the said armature I is connected to an arm, J, which forms aflexible joint with the post K, and the line electro-magnet L M is soplaced that the current will act upon the armature I and cause theroller H to bear with a corresponding pressure on the strip N, which isconnected to the diaphragm and passed-between the peripheral surfaces ofthe rollers. As `shown in Fig. 3, one ot' the rollers is provided withguiding-iianges to prevent the strip from becoming accidentallydisplaced. In Fig. l a permanent'magnet, 0, is shown connected to theline electro-magnet L M.

The armature I may be adjusted by means of a supporting-spring, P, and ascrew, Q, for varying the tension ot'the spring, andthe roller H, whichis supported bysaid armature, may be arranged either as shown in Fig. 1,where it is represented above the roller G, or as shown in Fig. 4, whereit nnder'said roller. In the latter case the adjusting-spring P isadapted to exert agiven pressure ofthe roller H against the strip, andthe vibrations ofthe diaphragm are produced bythe electro-motive forceexerted on the armature, thereby overcoming the tension of-sprng P andallowing` the strip to be released from pressure.

Instead of a flat strip, as shown in Fig. 3, l may sometimes use atriangular strip, as shown inFig. 5, and construct one ofthe rollerswith a V-groove to receive one ofthe edges ot' the triangular strip.

In Figs. 2 and 4 I have shown a perforated diaphragm arranged inside ofand parallel with the diaphragm B to form an air-chamber; but

IOO

Ido not attach any special importance to this tratare, and it may beomitted without aii'ecting the merits of' my invention.

Having thus described my invention, what I claim as new, and desire tosecure by Letters Patent, is-

1. In a telephone, the combination, with a diaphragm, of a strip ofsuitable material connected thereto and two rotating` rollers betweenwhich the strip is placed, an electromagnet, and an adjustable armaturesupporting' one of the rollers, substantially as shown and described.

2. In a telephone, the combination ofa roller supported in a stationaryl'rame and means for rotating' said roller, a second roller supported inan armature, an adjustable spring supporting; the armature, anelectro-magnet, and a strip of suitable material connected to adiaphragm and arranged between the rollers', substantially;T as shownand described.

phragm, substantially as shown and described. 35

GEO. A. FITCH.

Witnesses:

A. G. LYNE,

SoLoN C. KnMoN.

